1. Field of the Invention
The present invention relates to an image recording system, an image data resource apparatus, an image recording apparatus, an image processing method and a program for the image processing method each of which uses a matrix pattern process to expand image data into recording data corresponding to a predetermined dot matrix and record an image on a recording medium by using plural recording elements, and more particularly, to an image recording system, an image data resource apparatus, an image recording apparatus, an image processing method and a program for the image processing method each of which can provide a high-quality image at high speed.
2. Related Background Art
Conventionally, in a recording apparatus which records an image on a recording medium such as a paper or the like, it is intended to increase resolution of image data because a high-quality image is demanded. However, according as the resolution of the image data increases, an amount of data to be processed increases. For this reason, for example, there is a problem that a data processing time of a host computer (host apparatus, host PC (personal computer)) for transferring the image data to cause the recording apparatus (printer) to record the image, a transfer time of the image data from the host computer to the recording apparatus and the like are prolonged.
Incidentally, a matrix recording method which has been conventionally known is provided to solve the above problem. That is, in this matrix recording method, the image data processed by the host PC at relatively low resolution in higher-value quantization is transferred to the printer having plural recording elements (nozzles), and the received image data is expanded into recording data corresponding to a predetermined dot matrix and then printed by the printer. An example of the matrix recording method will be explained with reference to FIG. 12. As the processes in the host PC, FIG. 12 shows a case (A) of performing a high-resolution process (600 ppi) and a case of (B) of performing a matrix pattern process (300 ppi). Here, it should be noted that “ppi” indicates “pixels per inch”.
In the case (A) of performing the high-resolution process, if the image data is quantized with two levels in relation to 600 ppi, the recording is performed in units of four dots in relation to 300 ppi, and an actual recording dot layout includes 16 unit layouts as shown in FIG. 12. Then, the substantial density level of these 16 kinds of layouts can be treated as same as the case of the number of dots applied to a 300 ppi lattice structured in units of four dots, and thus includes five levels. On the other hand, in the case (B) of performing the matrix pattern process, the image data is quantized with five levels in relation to 300 ppi, and the these quantization levels are respectively allocated to “0” to “4” of the number of dots applied to the 300 ppi lattice structured in units of four dots as shown in FIG. 12. Therefore, even if the data amount decreases, gradation expression same as the recording result in the high-resolution process can be achieved.
In recent years, the resolution of the printer becomes higher, whereby the printer can form a larger number of dots than ever before. For this reason, the number of pixels to be recorded increases, and also the printer itself has a larger number of nozzles to improve print speed, whereby the above matrix recording method becomes important more than ever.
On one hand, recently, in case of performing image printing by a printer, a demand for doing so without using any PC increases. That is, as a system for enabling a user to easily use the Internet by one's side, various systems such as a WebTV™ system (service for connecting with the Internet by using TV (television)), a set-top box (terminal device attached to TV for connecting with the Internet), and the like in which an Internet function is added to a general TV are known. In this connection, a demand for causing the printer to print the image from such a so-called Non-PC system (system not using PC) increases.
On one hand, according to popularization of a digital camera, a demand for causing so-called a photo-direct (PD) printer or the like to store image data from the digital camera in a recording medium such as a CompactFlash™ (CF) card or the like, read the image data stored in the CF card through a card slot provided on the printer side, and then directly print the read image data without using any host PC increases. Moreover, a PD print system which causes the PD printer to perform the printing without using any recording medium has been achieved. That is, in the PD print system, the PD printer directly captures the image data from the digital camera through Universal Serial Bus (USB) or the like, converts the captured image data into data capable of being recorded on the PD printer side, and then actually prints the converted data.
The above PD printer includes an image processing function called a controller unit. Thus, various processes such as image rendering, rasterizing, color conversion, quantization, print control command generation and the like which are ordinarily performed on the host PC side are all performed on the controller unit side, and the processed data is then transferred from the controller unit to an engine unit. Then, the engine unit reads the transferred data, analyzes a print control command and print data from the read data, and thus performs mechanical control such as paper feeding control, carriage movement control and the like necessary to actually record the image on the recoding medium. Moreover, the engine unit performs control to apply a driving pulse to a recording head, control to transmit the data to the recording head, and the like. Here, it should be noted that the above control in the engine unit is the same as the control to be performed in a conventional case where the data from the host PC is received by the engine unit.
The general PD printer is often designed to add the controller unit on the printer being the base. Thus, in the printer designed as above, the controller unit is connected with the engine unit of the printer itself through an internal bus so that the data to be processed inside the engine unit may include not only the data sent from the controller unit but also the data processed and sent from the host PC, thereby achieving the printing.
However, it is apparent that the Non-PC system and the PD printer to which the demand increases in recent years have the following problems.
(1) Problems in Non-PC System
According as the performance of the PC increases in recent years, a printer driver on the PC is designed to be able to perform a process at satisfactory processing speed with high quality in an environment having an sufficient memory of several tens of megabytes (MB) and a high-speed CPU of gigahertz (GHz). On the other hand, since the Non-PC system such as the WebTV™ system, the set-top box or the like does not necessarily have the large-capacity memory and the high-speed CPU as above, if the process to be performed by the printer driver on the PC is applied to this system as it is, the problem that the image quality and speed same as above cannot be maintained occurs.
Moreover, even if the above matrix recording method is intended to be applied to solve this problem, in fact, it is too various and uncertain to assume beforehand methods for expanding the matrix patterns corresponding to the operation environments in the various Non-PC systems and prepare the assumed methods in the engine unit of the printer, whereby the problem that the engine unit of the printer suffers from excessive loads occurs. Therefore, it is thought that the above matrix recording method cannot be applied as a matter of fact.
Moreover, the resolution of the image data to be handled is different in relation to each Non-PC system. Thus, although achieved on the printer driver of the PC, the process cannot be necessarily achieved at the resolution required by a user. For this reason, the image output from the printer which can be achieved on the PC cannot be necessarily achieved on the Non-PC system. In the worst case, the problem that it is impossible to perform the printing might occur.
(2) Problems in PD Printer System
As well as the Non-PC system, it is impossible in the controller unit of the PD printer system to expect the large-capacity memory and the high-speed CPU as provided in the PC because these parts remarkably raise the cost. Thus, if the process to be performed by the printer driver on the PC is applied to this system as it is, the problem that the image quality and speed same as above cannot be maintained occurs. As a matter of fact, in the various PD printer systems which are currently commercialized, the products each of which can maximally utilize the print speed of the engine unit of its printer are few due to the problem of processing loads in the controller unit.
Moreover, even if the above matrix recording method is applied to solve this problem, it is necessary to previously incorporate a PD-dedicated specification in the engine unit of the printer being the base. However, this is the excessive specification for a simple body of this base printer, whereby the problem that such a specification might come to affect a program storage unit and the like occurs.
Particularly, in a case where the base printer has been already commercialized, the PD printer on which the controller unit is added cannot achieve in this controller unit the processing speed at the data resolution receivable by that printer, whereby the problem that the print speed inherent in the engine unit cannot be sufficiently satisfied occurs.
In summary, the system, which is expected to be further popularized in future, for outputting the image data from the devices other the PC to the printer roughly has the following two problems, that is, (1) if the process of the printer driver performed on the PC is directly applied as it is, the image quality and the speed (general speed including image processing speed, data transfer speed, and print speed) cannot be maintained because the load of the image processing unit in the printer increases, and (2) the operation environments for applying the matrix recording method to solve the above problem (1) are various, whereby it is difficult to entirely contain the appropriate matrix recording method within the printer engine.